>A diagram would be nice.  How close is the cold reservoir (CR ) to
> the tap ?

A diagram could be nice but here we go in << 1000 words:

Potable H20 flow: Leave bottom of reservoir, goes up about 2 m to tap.  At 
top is T'off to tap and goes back down thru check valve, T's in with 
incoming feed, and into top of reservoir.

Coolant loop flow: Leave coolant reservoir, go thru pump, peltier 
waterblock, heat exchanger in potable water reservoir, back to pump.

Heat dump: Hot side of TEC directly connected to output of large water 
container.

> If it is close why not have several TECs cool the water pipe feeding
> the tap ?
> In addition to one cooling the main CR.

I am assuming this is to avoid having to circulate the water to the tap.

> Have the TECs hot side connected to a small copper pipe ( SCP ) that
> runs from the
> cooling loop.  Use a non-potable pump to move water slowly through
> pipe and
> return it to the top of the cooling reservoir.

>When the TECs are off
> they
> can be retracted from contact with the SCP using a small motor and
> detecting
> stall current.

Seems like a lot of fuss to avoid the recirculation.

> Temp sensors
> How about a MAX6575 or equivalent.   built in 8 device multi-drop
> capability.
> 3 connections ( Vdd [ 2.7 to 5.5 V ] , GND, Common I/O )
>  $1.35 each    Is that too expensive ?

Not too bad. Surprisingly, even though I almost always put as much into SW 
as I can to simplify the HW, for this (one-off) project I might prefer 
something like the MAX6576 or MAX6577 instead, even at the cost of I/O pins 
or (shudder) an external multiplexor.


Thanks for the input,

Bob Ammerman
RAm Systems


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